I think that RC cars (or really rc anything) makes a great platform for hacking, you start with a chassis, motors, most of the control circuitry already in place and then you just have to interface a few of your own components and bam. you have a sweet robot. some students at my university made something similar to this using a long range xbee module and gps tracking.

Another thing that you could look into is to see if your motherboard has a serial interface, frequently the serial pinout exists on the mobo, but is not hooked up to an RS232 serial port since nobody besides wirebiters and nerds needs one. you can then find a serial port on-line that will interface with the pinout for like 3 bucks. The same is frequently true of parallel ports as well.

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